Disulfide stabilizers for 3-isothiazolones

Abstract

A method of stabilizing non-halogen containing 3-isothiazolone microbicides against chemical degradation by the introduction of aromatic disulfide compounds (except 2,2'-dithiobisbenzoic acid) is disclosed.

What is claimed is: 
     
       1. A method of stabilizing non-halogen containing 3-isothiazolone microbicides comprising introducing to said 3-isothiazolone at least one aromatic disulfide compound in an amount sufficient to stabilize said 3-isothiazolone, provided said aromatic disulfide compound is not 2,2'-dithiobisbenzoic acid. 
     
     
       2. Method according to claim 1 wherein said aromatic disulfide compound is selected from the group consisting of 2,2'-dithiobis(pyridine-N-oxide); 5,5'-dithiobis(2-nitrobenzoic acid); 2,2'-dithiobis(pyridine); 2,2'-dithiobis(benzothiazole); 2,2'-dithiobis(5-nitropyridine); and 5,5'-dithiobis(1-phenyl-1-H-tetrazole). 
     
     
       3. Method according to claim 1 wherein said 3-isothiazolone is selected from the group consisting of 2-methyl-3-isothiazolone; 2-n-octyl-3-isothiazolone; 2-ethyl-3-isothiazolone; and mixtures thereof. 
     
     
       4. Method according to claim 1 wherein the ratio of said 3-isothiazolone to said aromatic disulfide compound is from 10:1 to 1:10. 
     
     
       5. A composition comprising 3-isothiazolone microbicides and at least one aromatic disulfide compound selected from the group consisting of 2,2'-dithiobis(pyridine-N-oxide); 5,5'-dithiobis(2-nitrobenzoic acid); 2,2'-dithiobis(pyridine); 2,2'-dithiobis(benzothiazole); 2,2'-dithiobis(5-nitropyridine); and 5,5'-dithiobis(1-phenyl-1-H-tetrazole), wherein the aromatic disulfide is present in an amount sufficient to stabilize said 3-isothiazolone. 
     
     
       6. Composition according to claim 5 wherein said 3-isothiazolone is selected from the group consisting of 2-methyl-3-isothiazolone; 2-n-octyl-3-isothiazolone; 2-ethyl-3-isothiazolone; and mixtures thereof. 
     
     
       7. Composition according to claim 5 wherein the ratio of said 3-isothiazolone to said aromatic disulfide compound is from 10:1 to 1:10. 
     
     
       8. Composition according to claim 5 where in said 3-isothiazolone is selected from the group consisting of 2-methyl-3-isothiazolone and 2-n-octyl-3-isothiazolone; said aromatic disulfide compound is selected from the group consisting of 2,2'-dithiobis(pyridine-N-oxide) and 5,5'-dithiobis(2-nitrobenzoic acid); and the ratio of said 3-isothiazolone to said aromatic disulfide compound is from 1:10 to 10:1.